AcidSnake wrote:
(Chapter 6 spoiler) I haven't finished this chapter yet, in fact I think I'm at the beginning, but this is just exactly what I wanted...Some great backstory and nice recorded messages...That said I didn't like the fact that they already had an early version of the Portal gun (although laughably oversized)...I would've preferred that the puzzles were solvable without the Portal gun originally (as in 1961) and you'd use it only because the testing chambers had degraded and stairs had collapsed and so forth...I had my own mini story in my head where the Portal gun was actually thought up by GLaDOS and that's why she's so interested in testing it...Might still come true of course

More chapter-exclusive spoilers, and some Portal 1 stuff. While the first game was coy in sharing the facility's history, the fictitiously official website of Aperture did reveal that the teleportation project wasn't even thought of until the 70s, and the portal device was finished long after his death. Portal 2 changes that in order to justify giving you test chambers to solve. Here's a fun fact: Portal 2 started out as a prequel with no portals. Testers wanted familiarity, but Valve found a way to make use of old Aperture and Cave as a character.

It's highly unlikely GLaDOS invented the portal device, by the way, especially with Portal 2 finally confirming that it existed at the start of Aperture. GLaDOS is interested in all sorts of science, it's just that the device is centric to the franchise. It would be a bit odd if we were testing a new line of cheese graters or something.

AcidSnake wrote:
(General spoiler) Something I found different is that GLaDOS is now quite definitely operating at 100% whereas in the first game she would garble speech or switch to Spanish or have "subject home town here" lines...Again I'm just at Chapter 6, so she might go back to being herself...

You destroy her cores in Portal 1. Before you killed her, you freed her from all the artificial inhibitions the scientists attached to the chassis to control and influence her behaviour.